1. Field of the Invention
This invention pertains generally to leveling poured concrete and more particularly to an adjustable apparatus for supporting screed rails used in connection with leveling concrete.
2. Description of the Background Art
In order to provide smooth, uniform surfaces, freshly poured concrete must normally be spread over the area of the pour and "screeded" into place. A leveling device commonly known as a "screed" is drawn over the freshly poured concrete to ensure that a uniform layer results. Hand screeding, which is common in the industry, is a labor intensive task. When pouring and leveling concrete slabs directly on the ground, forms are used to frame the area of the pour. Typically the ground is uneven, thus making it difficult to obtain perfectly flat slabs. Wood forms, which are commonly held in place with stakes and nails, deteriorate with use over time. Similar problems are encountered when pouring concrete on metal or wood decks, and when pouring tilt-up wall panels. As a result, several approaches to concrete forming and leveling have been developed in an attempt to economically place concrete.
Examples of devices which move along rails or tracks for placing and leveling concrete can be found in U.S. Pat. No. 4,507,015 issued to Furukawa et al. on Mar. 26, 1985, which discloses a box-like screed apparatus which is guided by tracks or rails; U.S. Pat. No. 3,005,387 issued to Heltzel et al. on Oct. 24, 1971, which discloses a concrete grooving tool which has a guide bar which fits over a guide rail for accurately positioning the groove; and U.S. Pat. No. 3,404,611 issued to Wilson on Oct. 8, 1968, which discloses a reciprocating belt apparatus for finishing concrete which moves along rails supported from their underside by threaded jack members which can be positioned to the proper height. Those patents, however, do not present solutions for the positioning and placement of screed rails for hand finishing in areas where the devices disclosed cannot be used.
Examples of hand operated screed rail and rail support devices can be found in U.S. Pat. No. 4,913,582 issued to Barrett on Apr. 3, 1990, which discloses a screed chair having a base plate, a pipe, and at least one threaded vertical support which holds a horizontal saddle onto which a screed pipe is rested; U.S. Pat. No. 4,115,976 issued to Rohrer on Sep. 26, 1978, which discloses a screed support and method of screeding cement which comprises screed rails, and screed rail supports which are left in place after the concrete is poured but removed before the concrete hardens; U.S. Pat. No. 4,321,024 issued to Terraillon on Mar. 23, 1982, which discloses metal stands which rest on the ground and support removable metal forms; U.S. Pat. No. 1,169,464 issued to Cornelius on Jan. 25, 1916, which discloses portable forms and supports for molding concrete or cement curbing; U.S. Pat. No. 4,437,828 issued to Egger on Mar. 20, 1984, which discloses a screed bar support saddle which has vertical adjustable legs; and U.S. Pat. No. 4,934,643 issued to Militano on Jun. 19, 1990, which discloses a support for concrete screed rails which has an upright stake or post and uses a sleeve adjustably mounted on the post for movement along the post. Those patents, however, disclose devices which suffer from several disadvantages. For example, when pouring concrete on a steel or otherwise impenetrable deck, with some of the devices disclosed it would be necessary to drill holes in the deck material for placement of the forms or screed rail supports. Punctures in a waterproof membrane often used with concrete slabs can also occur with some of the devices disclosed. Also, it can be quite difficult to obtain a transit sight or to position a string line at the finished slab height with many of the devices heretofore developed. Many of the devices heretofore developed are labor intensive, are costly to set-up and use, and do not provide for easy relocation and re-use of the screed rails after a section of concrete is poured and leveled.
The present invention overcomes the aforementioned as well as other deficiencies in the devices heretofore developed and provides a screed rail support mechanism which can be easily placed and removed from a graded surface in conjunction with the pouring of concrete.
The foregoing patents reflect the state of the art of which the applicant is aware and are tendered with the view toward discharging applicant's acknowledged duty of candor in disclosing information which may be pertinent in the examination of this application. It is respectfully stipulated, however, that none of these patents teach or render obvious, singly or when considered in combination, applicant's claimed invention.